1. Field of the Invention
The present invention is related to a waveform processing apparatus and an electronic musical instrument in which the waveform processed by the apparatus is stored in a waveform memory, and particularly to correction of waveform data when the waveform is repeatedly read out from the waveform memory.
2. Description of the Prior Art
In the conventional electronic musical instrument, there were methods in which musical tones are stored in a waveform memory, and read out based on play information such as key-on to produce musical tone signals. Among them, there was a method in which to provide delicate change of tone color in the attack portion immediately after a key-on and the succeeding decay and sustain portions, the original tone of a musical instrument is recorded from the start to the end of tone generation and stored in a waveform memory. In this case, since the latter-half waveform had little tone color change, there was a method in which the capacity of waveform memory was saved by repeatedly reading out the same waveform section after the elapse of a certain period of time.
In natural sound, generally both the frequency and amplitude components are changing with time. However, in the conventional electronic musical instrument as described above, there was a problem that the spectral change with time suddenly disappears when the period for repetition reading from the waveform memory is entered, thus providing an unnatural feeling.